1. Field of the Invention
This device relates to a vacuum cleaner, and more particularly, this device is for adjusting a length of a suction pipe of a large capacity vacuum cleaner capable of adjusting the length of the suction pipe appropriately according to need of situation.
2. Description of the Related Art
Generally, a vacuum cleaner generates a strong suction force in a dust chamber by a driving of a motor mounted in a cleaner body. The dust chamber is connected to a suction pipe through a flexible hose, and accordingly, air and ambient contaminants are drawn into the dust chamber through the suction pipe and the flexible hose. Accordingly, the cleaning process is performed automatically. Meanwhile, when the length of the hose or the suction pipe is improper for user""s desired cleaning place, i.e., when the hose or the suction pipe is shorter or longer than the user requires, then the user adjusts the length of the suction pipe excluding the hose which is not adjustable.
FIG. 1 schematically shows the construction of the conventional device for adjusting the length of the suction pipe of a vacuum cleaner, which is representatively disclosed in the EP 0 552 481 A1. The length adjusting device includes an outer pipe 12 having an extended portion 12-1 on which a mount portion 12-2 is defined, an inner pipe 11 fit in the outer pipe 12 and having locking recesses 25 formed on an outer circumference of the inner pipe 11 at a predetermined distance from each other, a guide body 15 fit between the extended portion 12-1 and the inner pipe 11 and having an opening 24 formed in the middle portion, and also having seating portions 15-1, coil springs 22, each of which having one end connected to one end of each seating portion 15-1 of the guide body 15, an operating portion 17 to which the other end of each coil spring 22 is connected, and moved in the lengthwise direction by a recovering force of each coil spring 22, and having a pressing portion 17-1 formed on a lower middle portion, and also having escaping recesses 17-2 defined at both sides of the pressing portion 17-1, a slide 16 having a lower portion mounted on an upper surface of the operating portion 17 by fastening projections 17-3 in a manner of being exposed to the mount portion 12-2, and a roller 7 inserted in the opening 24, thus locked in or released from the locking recesses 25.
When the user moves the slide 16 in the lengthwise direction of the suction pipe 10, the roller 26 is released from the restricted state, and accordingly, the opening 24 is aligned with one of the escaping recess 17-2. Then when the user moves the inner pipe 11 in the lengthwise direction, the roller 26 is separated from the locking recess 25, and inserted in the escaping recess 17-2. Accordingly, the length of the suction pipe 10 can be adjusted appropriately. Then, as the user stops exerting the force to the slide 16, the slide 16 is returned to the middle portion of the guide body 15 by the recovering force of the coil springs 22, and accordingly, the pressing portion 17-1 of the operating portion 17 re-presses the roller 26.
In the conventional device for adjusting the length of the suction pipe, however, the operating portion 17 and the slide 16 have to be prepared separately, and then integrally assembled with each other. Further, the end of the outer pipe 12 should be extended to receive the guide body 15. Accordingly, the manufacturing process becomes complex.
In order to solve the above-mentioned problem of the prior art, the same applicant disclosed an improved device for adjusting the length of the suction pipe of the vacuum cleaner in the Korean Patent Application No. 99-16556 (Filed May 10, 1999 and entitled: Device for adjusting suction pipe length of a vacuum cleaner). According to the Korean Patent Application No. 99-16556 as shown in FIGS. 2A and 2B, a sleeve 3 having a long hole 3a is fastened at one end of an outer pipe 2. The long hole 3a is formed in the middle portion of the sleeve 3 in a circumferential direction. A pair of elastic rings 6 are disposed on the outer circumference of both ends of the sleeve 3 at a predetermined distance from each other, in a manner that certain portion of the elastic rings 6 are fixed on the outer circumference of the sleeve 3. The long hole 3a of the sleeve 3 receives a locking pin 5 which is locked in one of locking recesses 1a that are formed on the inner pipe 1 at a predetermined distance from each other in a lengthwise direction. On the inner circumference of the sleeve 3, guide projections 3b is formed for being inserted in one of guide grooves 1b formed on the outer circumference of the inner pipe 1 in the lengthwise direction. On the outer circumference of both ends of the sleeve 3, annular limiting projections 3c are formed, respectively. On the outer circumference of the sleeve 3, a sliding cover 4 is mounted. The sliding cover 4 has a pair of arc locking projections 4a formed on the inner circumference of the sliding cover 4 and positioned at the outer side of the annular rings 6, respectively. Between the locking projections 4a, there are formed a pressing projection 4b for pressing the locking pin 5, and a pair of escaping recesses 4c to which the locking pin 5 is selectively received, respectively.
Accordingly, by moving the sliding cover 4 forward or backward, one of the escaping recesses 4c is aligned with the locking pin 5. Accordingly, the locking pin 5 is released from the restricted state, and the inner pipe 1 can be moved freely with respect to the outer pipe 2. Then, by discontinuing an application of force to the sliding cover 4, the sliding cover 4 returned to the original position by the recovering force of the elastic ring 6, and accordingly, the locking pin 5 is inserted in one of the locking recesses I a of the inner pipe 1. Then, pressed by the pressing projection 4b, the inner pipe 1 is fixed at the position.
According to the Korean Patent Application No. 99-16556, the locking pin 5 is separately prepared and inserted in only one locking recess 1a of the inner pipe 1 to serve its function of fixing a position. Further, since the locking pin 5 is simply inserted in the long hole 3a of the sleeve 3, there is a possibility that the locking pin 5 may be separated. Further, the sleeve 3 and the sliding cover 4, which are made of metal material, does not operate smoothly, and also causes a considerable level of friction noise.
This device has been made to overcome the above-mentioned problems of the related arts, and accordingly, it is an object to provide a device for adjusting a length of a suction pipe of a vacuum cleaner, capable of firmly positioning an inner pipe at a desired location, regardless of external shocks, or the like.
Another object is to provide a device for adjusting a length of a suction pipe of a vacuum cleaner that is smoothly operated, while minimizing the level of friction noise.
The above objects are accomplished by a present device for adjusting a length of a suction pipe of a vacuum cleaner, including a sleeve securely connected to one end of an outer pipe, and having a pair of limiting projections formed on an outer circumference of the outer pipe in a circumferential direction and axially spaced from each other by a predetermined distance, a slot defined between the pair of limiting projections in an axial direction, and a guide projection formed on the inner circumference of the sleeve for being inserted in a guide recess formed on an outer circumference of an inner pipe in an axial direction of the inner pipe; a locking plate inserted in the slot of the sleeve, and having a pair of locking projections formed on a lower surface of the locking plate and inserted in at least a pair of neighboring locking recesses which are formed on the outer circumference of the inner pipe and spaced from each other by a predetermined distance in an axial direction; a pair of arc-shaped pressing plates connected between the pair of limiting projections of the sleeve for restricting the locking plate, the pressing plates having cam grooves, respectively, along which the pressing plates are moved in a circumferential direction to opposite directions to selectively release the locking plate; and a sliding cover movably connected on the outer circumference of the sleeve in an axial direction, and securely positioned at a predetermined position by elastic means, the sliding cover having operating projections which are movably inserted in the cam grooves of the pair of pressing plates.
According to the present device, the elastic means includes a seating recess formed on the outer circumference of the sleeve in an axial direction, facing the slot; a supporting projection formed on the inner circumference of the sliding cover and positioned in a middle of the seating groove, dividing the seating groove into a pair of half grooves; and coil springs inserted in the half grooves of the seating groove.
According to another preferred aspect of the present device, respective portions, such as the sleeve, the locking plate, the pressing plates, and the sliding cover, are formed of a rigid synthetic resin, such as an ABS, or the like.
Accordingly, since at least a pair of locking projections are locked in the pair of locking recesses of the inner pipe, the inner pipe can be securely positioned.